/******************************************************
Undo modify of a row

(c) 1997 Innobase Oy

Created 2/27/1997 Heikki Tuuri
*******************************************************/

#include "row0umod.h"

#ifdef UNIV_NONINL
#include "row0umod.ic"
#endif

#include "dict0dict.h"
#include "dict0boot.h"
#include "trx0undo.h"
#include "trx0roll.h"
#include "btr0btr.h"
#include "mach0data.h"
#include "row0undo.h"
#include "row0vers.h"
#include "trx0trx.h"
#include "trx0rec.h"
#include "row0row.h"
#include "row0upd.h"
#include "que0que.h"
#include "log0log.h"

/* Considerations on undoing a modify operation.
(1) Undoing a delete marking: all index records should be found. Some of
them may have delete mark already FALSE, if the delete mark operation was
stopped underway, or if the undo operation ended prematurely because of a
system crash.
(2) Undoing an update of a delete unmarked record: the newer version of
an updated secondary index entry should be removed if no prior version
of the clustered index record requires its existence. Otherwise, it should
be delete marked.
(3) Undoing an update of a delete marked record. In this kind of update a
delete marked clustered index record was delete unmarked and possibly also
some of its fields were changed. Now, it is possible that the delete marked
version has become obsolete at the time the undo is started. */

/***************************************************************
Checks if also the previous version of the clustered index record was
modified or inserted by the same transaction, and its undo number is such
that it should be undone in the same rollback. */
UNIV_INLINE
ibool row_undo_mod_undo_also_prev_vers(
    /*=============================*/
    /* out: TRUE if also previous modify or
    insert of this row should be undone */
    undo_node_t *node, /* in: row undo node */
    dulint *undo_no)   /* out: the undo number */
{
  trx_undo_rec_t *undo_rec;
  trx_t *trx;

  trx = node->trx;

  if (0 != ut_dulint_cmp(node->new_trx_id, trx->id))
  {
    *undo_no = ut_dulint_zero;
    return (FALSE);
  }

  undo_rec = trx_undo_get_undo_rec_low(node->new_roll_ptr, node->heap);

  *undo_no = trx_undo_rec_get_undo_no(undo_rec);

  return (ut_dulint_cmp(trx->roll_limit, *undo_no) <= 0);
}

/***************************************************************
Undoes a modify in a clustered index record. */
static ulint row_undo_mod_clust_low(
    /*===================*/
    /* out: DB_SUCCESS, DB_FAIL, or error code:
    we may run out of file space */
    undo_node_t *node, /* in: row undo node */
    que_thr_t *thr,    /* in: query thread */
    mtr_t *mtr,        /* in: mtr */
    ulint mode)        /* in: BTR_MODIFY_LEAF or BTR_MODIFY_TREE */
{
  big_rec_t *dummy_big_rec;
  btr_pcur_t *pcur;
  btr_cur_t *btr_cur;
  ulint err;
  ibool success;

  pcur = &(node->pcur);
  btr_cur = btr_pcur_get_btr_cur(pcur);

  success = btr_pcur_restore_position(mode, pcur, mtr);

  ut_ad(success);

  if (mode == BTR_MODIFY_LEAF)
  {
    err = btr_cur_optimistic_update(BTR_NO_LOCKING_FLAG | BTR_NO_UNDO_LOG_FLAG | BTR_KEEP_SYS_FLAG, btr_cur,
                                    node->update, node->cmpl_info, thr, mtr);
  }
  else
  {
    ut_ad(mode == BTR_MODIFY_TREE);

    err = btr_cur_pessimistic_update(BTR_NO_LOCKING_FLAG | BTR_NO_UNDO_LOG_FLAG | BTR_KEEP_SYS_FLAG, btr_cur,
                                     &dummy_big_rec, node->update, node->cmpl_info, thr, mtr);
  }

  return (err);
}

/***************************************************************
Removes a clustered index record after undo if possible. */
static ulint row_undo_mod_remove_clust_low(
    /*==========================*/
    /* out: DB_SUCCESS, DB_FAIL, or error code:
    we may run out of file space */
    undo_node_t *node,                      /* in: row undo node */
    que_thr_t *thr __attribute__((unused)), /* in: query thread */
    mtr_t *mtr,                             /* in: mtr */
    ulint mode)                             /* in: BTR_MODIFY_LEAF or BTR_MODIFY_TREE */
{
  btr_pcur_t *pcur;
  btr_cur_t *btr_cur;
  ulint err;
  ibool success;

  pcur = &(node->pcur);
  btr_cur = btr_pcur_get_btr_cur(pcur);

  success = btr_pcur_restore_position(mode, pcur, mtr);

  if (!success)
  {
    return (DB_SUCCESS);
  }

  /* Find out if we can remove the whole clustered index record */

  if (node->rec_type == TRX_UNDO_UPD_DEL_REC && !row_vers_must_preserve_del_marked(node->new_trx_id, mtr))
  {
    /* Ok, we can remove */
  }
  else
  {
    return (DB_SUCCESS);
  }

  if (mode == BTR_MODIFY_LEAF)
  {
    success = btr_cur_optimistic_delete(btr_cur, mtr);

    if (success)
    {
      err = DB_SUCCESS;
    }
    else
    {
      err = DB_FAIL;
    }
  }
  else
  {
    ut_ad(mode == BTR_MODIFY_TREE);

    /* Note that since this operation is analogous to purge,
    we can free also inherited externally stored fields:
    hence the last FALSE in the call below */

    btr_cur_pessimistic_delete(&err, FALSE, btr_cur, FALSE, mtr);

    /* The delete operation may fail if we have little
    file space left: TODO: easiest to crash the database
    and restart with more file space */
  }

  return (err);
}

/***************************************************************
Undoes a modify in a clustered index record. Sets also the node state for the
next round of undo. */
static ulint row_undo_mod_clust(
    /*===============*/
    /* out: DB_SUCCESS or error code: we may run
    out of file space */
    undo_node_t *node, /* in: row undo node */
    que_thr_t *thr)    /* in: query thread */
{
  btr_pcur_t *pcur;
  mtr_t mtr;
  ulint err;
  ibool success;
  ibool more_vers;
  dulint new_undo_no;

  ut_ad(node && thr);

  /* Check if also the previous version of the clustered index record
  should be undone in this same rollback operation */

  more_vers = row_undo_mod_undo_also_prev_vers(node, &new_undo_no);

  pcur = &(node->pcur);

  mtr_start(&mtr);

  /* Try optimistic processing of the record, keeping changes within
  the index page */

  err = row_undo_mod_clust_low(node, thr, &mtr, BTR_MODIFY_LEAF);

  if (err != DB_SUCCESS)
  {
    btr_pcur_commit_specify_mtr(pcur, &mtr);

    /* We may have to modify tree structure: do a pessimistic
    descent down the index tree */

    mtr_start(&mtr);

    err = row_undo_mod_clust_low(node, thr, &mtr, BTR_MODIFY_TREE);
  }

  btr_pcur_commit_specify_mtr(pcur, &mtr);

  if (err == DB_SUCCESS && node->rec_type == TRX_UNDO_UPD_DEL_REC)
  {
    mtr_start(&mtr);

    err = row_undo_mod_remove_clust_low(node, thr, &mtr, BTR_MODIFY_LEAF);
    if (err != DB_SUCCESS)
    {
      btr_pcur_commit_specify_mtr(pcur, &mtr);

      /* We may have to modify tree structure: do a
      pessimistic descent down the index tree */

      mtr_start(&mtr);

      err = row_undo_mod_remove_clust_low(node, thr, &mtr, BTR_MODIFY_TREE);
    }

    btr_pcur_commit_specify_mtr(pcur, &mtr);
  }

  node->state = UNDO_NODE_FETCH_NEXT;

  trx_undo_rec_release(node->trx, node->undo_no);

  if (more_vers && err == DB_SUCCESS)
  {
    /* Reserve the undo log record to the prior version after
    committing &mtr: this is necessary to comply with the latching
    order, as &mtr may contain the fsp latch which is lower in
    the latch hierarchy than trx->undo_mutex. */

    success = trx_undo_rec_reserve(node->trx, new_undo_no);

    if (success)
    {
      node->state = UNDO_NODE_PREV_VERS;
    }
  }

  return (err);
}

/***************************************************************
Delete marks or removes a secondary index entry if found. */
static ulint row_undo_mod_del_mark_or_remove_sec_low(
    /*====================================*/
    /* out: DB_SUCCESS, DB_FAIL, or
    DB_OUT_OF_FILE_SPACE */
    undo_node_t *node,   /* in: row undo node */
    que_thr_t *thr,      /* in: query thread */
    dict_index_t *index, /* in: index */
    dtuple_t *entry,     /* in: index entry */
    ulint mode)          /* in: latch mode BTR_MODIFY_LEAF or
                         BTR_MODIFY_TREE */
{
  ibool found;
  btr_pcur_t pcur;
  btr_cur_t *btr_cur;
  ibool success;
  ibool old_has;
  ulint err;
  mtr_t mtr;
  mtr_t mtr_vers;

  log_free_check();
  mtr_start(&mtr);

  found = row_search_index_entry(index, entry, mode, &pcur, &mtr);

  btr_cur = btr_pcur_get_btr_cur(&pcur);

  if (!found)
  {
    /* Not found */

    btr_pcur_close(&pcur);
    mtr_commit(&mtr);

    return (DB_SUCCESS);
  }

  /* We should remove the index record if no prior version of the row,
  which cannot be purged yet, requires its existence. If some requires,
  we should delete mark the record. */

  mtr_start(&mtr_vers);

  success = btr_pcur_restore_position(BTR_SEARCH_LEAF, &(node->pcur), &mtr_vers);
  ut_a(success);

  old_has = row_vers_old_has_index_entry(FALSE, btr_pcur_get_rec(&(node->pcur)), &mtr_vers, index, entry);
  if (old_has)
  {
    err = btr_cur_del_mark_set_sec_rec(BTR_NO_LOCKING_FLAG, btr_cur, TRUE, thr, &mtr);
    ut_ad(err == DB_SUCCESS);
  }
  else
  {
    /* Remove the index record */

    if (mode == BTR_MODIFY_LEAF)
    {
      success = btr_cur_optimistic_delete(btr_cur, &mtr);
      if (success)
      {
        err = DB_SUCCESS;
      }
      else
      {
        err = DB_FAIL;
      }
    }
    else
    {
      ut_ad(mode == BTR_MODIFY_TREE);

      btr_cur_pessimistic_delete(&err, FALSE, btr_cur, TRUE, &mtr);

      /* The delete operation may fail if we have little
      file space left: TODO: easiest to crash the database
      and restart with more file space */
    }
  }

  btr_pcur_commit_specify_mtr(&(node->pcur), &mtr_vers);
  btr_pcur_close(&pcur);
  mtr_commit(&mtr);

  return (err);
}

/***************************************************************
Delete marks or removes a secondary index entry if found.
NOTE that if we updated the fields of a delete-marked secondary index record
so that alphabetically they stayed the same, e.g., 'abc' -> 'aBc', we cannot
return to the original values because we do not know them. But this should
not cause problems because in row0sel.c, in queries we always retrieve the
clustered index record or an earlier version of it, if the secondary index
record through which we do the search is delete-marked. */
static ulint row_undo_mod_del_mark_or_remove_sec(
    /*================================*/
    /* out: DB_SUCCESS or DB_OUT_OF_FILE_SPACE */
    undo_node_t *node,   /* in: row undo node */
    que_thr_t *thr,      /* in: query thread */
    dict_index_t *index, /* in: index */
    dtuple_t *entry)     /* in: index entry */
{
  ulint err;

  err = row_undo_mod_del_mark_or_remove_sec_low(node, thr, index, entry, BTR_MODIFY_LEAF);
  if (err == DB_SUCCESS)
  {
    return (err);
  }

  err = row_undo_mod_del_mark_or_remove_sec_low(node, thr, index, entry, BTR_MODIFY_TREE);
  return (err);
}

/***************************************************************
Delete unmarks a secondary index entry which must be found. It might not be
delete-marked at the moment, but it does not harm to unmark it anyway. We also
need to update the fields of the secondary index record if we updated its
fields but alphabetically they stayed the same, e.g., 'abc' -> 'aBc'. */
static ulint row_undo_mod_del_unmark_sec_and_undo_update(
    /*========================================*/
    /* out: DB_FAIL or DB_SUCCESS or
    DB_OUT_OF_FILE_SPACE */
    ulint mode,          /* in: search mode: BTR_MODIFY_LEAF or
                         BTR_MODIFY_TREE */
    que_thr_t *thr,      /* in: query thread */
    dict_index_t *index, /* in: index */
    dtuple_t *entry)     /* in: index entry */
{
  mem_heap_t *heap;
  btr_pcur_t pcur;
  upd_t *update;
  ulint err = DB_SUCCESS;
  ibool found;
  big_rec_t *dummy_big_rec;
  mtr_t mtr;
  trx_t *trx = thr_get_trx(thr);

  log_free_check();
  mtr_start(&mtr);

  found = row_search_index_entry(index, entry, mode, &pcur, &mtr);

  if (!found)
  {
    fputs(
        "InnoDB: error in sec index entry del undo in\n"
        "InnoDB: ",
        stderr);
    dict_index_name_print(stderr, trx, index);
    fputs(
        "\n"
        "InnoDB: tuple ",
        stderr);
    dtuple_print(stderr, entry);
    fputs(
        "\n"
        "InnoDB: record ",
        stderr);
    rec_print(stderr, btr_pcur_get_rec(&pcur), index);
    putc('\n', stderr);
    trx_print(stderr, trx, 0);
    fputs(
        "\n"
        "InnoDB: Submit a detailed bug report to http://bugs.mysql.com\n",
        stderr);
  }
  else
  {
    btr_cur_t *btr_cur = btr_pcur_get_btr_cur(&pcur);

    err = btr_cur_del_mark_set_sec_rec(BTR_NO_LOCKING_FLAG, btr_cur, FALSE, thr, &mtr);
    ut_a(err == DB_SUCCESS);
    heap = mem_heap_create(100);

    update = row_upd_build_sec_rec_difference_binary(index, entry, btr_cur_get_rec(btr_cur), trx, heap);
    if (upd_get_n_fields(update) == 0)
    {
      /* Do nothing */
    }
    else if (mode == BTR_MODIFY_LEAF)
    {
      /* Try an optimistic updating of the record, keeping
      changes within the page */

      err = btr_cur_optimistic_update(BTR_KEEP_SYS_FLAG | BTR_NO_LOCKING_FLAG, btr_cur, update, 0, thr, &mtr);
      if (err == DB_OVERFLOW || err == DB_UNDERFLOW)
      {
        err = DB_FAIL;
      }
    }
    else
    {
      ut_a(mode == BTR_MODIFY_TREE);
      err = btr_cur_pessimistic_update(BTR_KEEP_SYS_FLAG | BTR_NO_LOCKING_FLAG, btr_cur, &dummy_big_rec, update, 0, thr,
                                       &mtr);
    }

    mem_heap_free(heap);
  }

  btr_pcur_close(&pcur);
  mtr_commit(&mtr);

  return (err);
}

/***************************************************************
Undoes a modify in secondary indexes when undo record type is UPD_DEL. */
static ulint row_undo_mod_upd_del_sec(
    /*=====================*/
    /* out: DB_SUCCESS or DB_OUT_OF_FILE_SPACE */
    undo_node_t *node, /* in: row undo node */
    que_thr_t *thr)    /* in: query thread */
{
  mem_heap_t *heap;
  dtuple_t *entry;
  dict_index_t *index;
  ulint err;

  heap = mem_heap_create(1024);

  while (node->index != NULL)
  {
    index = node->index;

    entry = row_build_index_entry(node->row, index, heap);

    err = row_undo_mod_del_mark_or_remove_sec(node, thr, index, entry);
    if (err != DB_SUCCESS)
    {
      mem_heap_free(heap);

      return (err);
    }

    node->index = dict_table_get_next_index(node->index);
  }

  mem_heap_free(heap);

  return (DB_SUCCESS);
}

/***************************************************************
Undoes a modify in secondary indexes when undo record type is DEL_MARK. */
static ulint row_undo_mod_del_mark_sec(
    /*======================*/
    /* out: DB_SUCCESS or DB_OUT_OF_FILE_SPACE */
    undo_node_t *node, /* in: row undo node */
    que_thr_t *thr)    /* in: query thread */
{
  mem_heap_t *heap;
  dtuple_t *entry;
  dict_index_t *index;
  ulint err;

  heap = mem_heap_create(1024);

  while (node->index != NULL)
  {
    index = node->index;

    entry = row_build_index_entry(node->row, index, heap);

    err = row_undo_mod_del_unmark_sec_and_undo_update(BTR_MODIFY_LEAF, thr, index, entry);
    if (err == DB_FAIL)
    {
      err = row_undo_mod_del_unmark_sec_and_undo_update(BTR_MODIFY_TREE, thr, index, entry);
    }

    if (err != DB_SUCCESS)
    {
      mem_heap_free(heap);

      return (err);
    }

    node->index = dict_table_get_next_index(node->index);
  }

  mem_heap_free(heap);

  return (DB_SUCCESS);
}

/***************************************************************
Undoes a modify in secondary indexes when undo record type is UPD_EXIST. */
static ulint row_undo_mod_upd_exist_sec(
    /*=======================*/
    /* out: DB_SUCCESS or DB_OUT_OF_FILE_SPACE */
    undo_node_t *node, /* in: row undo node */
    que_thr_t *thr)    /* in: query thread */
{
  mem_heap_t *heap;
  dtuple_t *entry;
  dict_index_t *index;
  ulint err;

  if (node->cmpl_info & UPD_NODE_NO_ORD_CHANGE)
  {
    /* No change in secondary indexes */

    return (DB_SUCCESS);
  }

  heap = mem_heap_create(1024);

  while (node->index != NULL)
  {
    index = node->index;

    if (row_upd_changes_ord_field_binary(node->row, node->index, node->update))
    {
      /* Build the newest version of the index entry */
      entry = row_build_index_entry(node->row, index, heap);

      /* NOTE that if we updated the fields of a
      delete-marked secondary index record so that
      alphabetically they stayed the same, e.g.,
      'abc' -> 'aBc', we cannot return to the original
      values because we do not know them. But this should
      not cause problems because in row0sel.c, in queries
      we always retrieve the clustered index record or an
      earlier version of it, if the secondary index record
      through which we do the search is delete-marked. */

      err = row_undo_mod_del_mark_or_remove_sec(node, thr, index, entry);
      if (err != DB_SUCCESS)
      {
        mem_heap_free(heap);

        return (err);
      }

      /* We may have to update the delete mark in the
      secondary index record of the previous version of
      the row. We also need to update the fields of
      the secondary index record if we updated its fields
      but alphabetically they stayed the same, e.g.,
      'abc' -> 'aBc'. */

      row_upd_index_replace_new_col_vals(entry, index, node->update, NULL);
      err = row_undo_mod_del_unmark_sec_and_undo_update(BTR_MODIFY_LEAF, thr, index, entry);
      if (err == DB_FAIL)
      {
        err = row_undo_mod_del_unmark_sec_and_undo_update(BTR_MODIFY_TREE, thr, index, entry);
      }

      if (err != DB_SUCCESS)
      {
        mem_heap_free(heap);

        return (err);
      }
    }

    node->index = dict_table_get_next_index(node->index);
  }

  mem_heap_free(heap);

  return (DB_SUCCESS);
}

/***************************************************************
Parses the row reference and other info in a modify undo log record. */
static void row_undo_mod_parse_undo_rec(
    /*========================*/
    undo_node_t *node, /* in: row undo node */
    que_thr_t *thr)    /* in: query thread */
{
  dict_index_t *clust_index;
  byte *ptr;
  dulint undo_no;
  dulint table_id;
  dulint trx_id;
  dulint roll_ptr;
  ulint info_bits;
  ulint type;
  ulint cmpl_info;
  ibool dummy_extern;
  trx_t *trx;

  ut_ad(node && thr);
  trx = thr_get_trx(thr);
  ptr = trx_undo_rec_get_pars(node->undo_rec, &type, &cmpl_info, &dummy_extern, &undo_no, &table_id);
  node->rec_type = type;

  node->table = dict_table_get_on_id(table_id, trx);

  /* TODO: other fixes associated with DROP TABLE + rollback in the
  same table by another user */

  if (node->table == NULL)
  {
    /* Table was dropped */
    return;
  }

  if (node->table->ibd_file_missing)
  {
    /* We skip undo operations to missing .ibd files */
    node->table = NULL;

    return;
  }

  clust_index = dict_table_get_first_index(node->table);

  ptr = trx_undo_update_rec_get_sys_cols(ptr, &trx_id, &roll_ptr, &info_bits);

  ptr = trx_undo_rec_get_row_ref(ptr, clust_index, &(node->ref), node->heap);

  trx_undo_update_rec_get_update(ptr, clust_index, type, trx_id, roll_ptr, info_bits, trx, node->heap, &(node->update));
  node->new_roll_ptr = roll_ptr;
  node->new_trx_id = trx_id;
  node->cmpl_info = cmpl_info;
}

/***************************************************************
Undoes a modify operation on a row of a table. */

ulint row_undo_mod(
    /*=========*/
    /* out: DB_SUCCESS or error code */
    undo_node_t *node, /* in: row undo node */
    que_thr_t *thr)    /* in: query thread */
{
  ibool found;
  ulint err;

  ut_ad(node && thr);
  ut_ad(node->state == UNDO_NODE_MODIFY);

  row_undo_mod_parse_undo_rec(node, thr);

  if (node->table == NULL)
  {
    found = FALSE;
  }
  else
  {
    found = row_undo_search_clust_to_pcur(node);
  }

  if (!found)
  {
    /* It is already undone, or will be undone by another query
    thread, or table was dropped */

    trx_undo_rec_release(node->trx, node->undo_no);
    node->state = UNDO_NODE_FETCH_NEXT;

    return (DB_SUCCESS);
  }

  node->index = dict_table_get_next_index(dict_table_get_first_index(node->table));

  if (node->rec_type == TRX_UNDO_UPD_EXIST_REC)
  {
    err = row_undo_mod_upd_exist_sec(node, thr);
  }
  else if (node->rec_type == TRX_UNDO_DEL_MARK_REC)
  {
    err = row_undo_mod_del_mark_sec(node, thr);
  }
  else
  {
    ut_ad(node->rec_type == TRX_UNDO_UPD_DEL_REC);
    err = row_undo_mod_upd_del_sec(node, thr);
  }

  if (err != DB_SUCCESS)
  {
    return (err);
  }

  err = row_undo_mod_clust(node, thr);

  return (err);
}
